Refraction of Light Through Plane and Curved Surfaces

Question 1

What is refraction and how is it explained in terms of the velocity of light in different media?

Answer 1

Refraction is the bending of light as it passes from one medium to another with a different density. It occurs because light travels at different speeds in different media; light slows down when moving from a less dense (e.g., air) to a denser medium (e.g., water), causing it to bend towards the normal.

Question 3

What are the laws of refraction?

Answer 3

The laws of refraction are:

The incident ray, refracted ray, and the normal all lie in the same plane.
The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant, known as Snell’s law:
𝑛_1 sin𝜃_1 = 𝑛_2 sin𝜃_2

Question 3

What is the refractive index of a medium?

Answer 3

The refractive index (𝑛) of a medium is the ratio of the speed of light in a vacuum to the speed of light in that medium. It quantifies how much the light bends when entering the medium.

Question 4

Q: How can you determine the refractive index of glass or a liquid using Snell’s law?

Answer 4

By measuring the angles of incidence and refraction as light passes from one medium to another and applying Snell’s law:
𝑛 = sin 𝜃_1 / sin 𝜃_2

Question 4

What are real and apparent depth?

Answer 4

Real depth is the actual depth of an object in a medium, while apparent depth is the depth at which the object appears to be when viewed from above the medium due to refraction. The relationship is given by

ApparentDepth = RealDepth / RefractiveIndex

Question 5

What is lateral displacement in refraction?

Answer 5

Lateral displacement is the sideways shift of a light ray as it passes through a transparent medium with parallel sides, like a glass slab.

Question 6

What are the critical angle and total internal reflection?

Answer 6

The critical angle is the angle of incidence in a denser medium at which the angle of refraction in the less dense medium is 90°. Total internal reflection occurs when the angle of incidence exceeds the critical angle, causing all the light to reflect back into the denser medium.

Question 7

What are the types of lenses and their uses?

Answer 7

**Convex lenses (converging): **
Bring light rays together; used in magnifying glasses, cameras, and glasses for farsightedness.

Concave lenses (diverging): Spread light rays apart; used in glasses for nearsightedness.

Question 8

What is the lens formula and how is it used?

Answer 8

The lens formula is
1 / 𝑓 = 1 / 𝑢 + 1 / 𝑣
where 𝑓 is the focal length,
𝑢 is the object distance, and
𝑣 is the image distance. It’s used to find the position and nature of the image formed by a lens.

Question 9

How is magnification related to lenses?

Answer 9

Magnification (𝑀) is the ratio of the height of the image (ℎ𝑖) to the height of the object (ℎ𝑜) and is given by 𝑀 = 𝑣 / 𝑢
where 𝑣 is the image distance and 𝑢 is the object distance.